The likehood of cold ("Florida cold", that is) weather is equal to the likelihood of warm weather at that time of year. The high could barely break 50, or be 85. It's anyone's guess (and the day after could be the exact opposite).
The water areas at discovery cove are quite warm, with the exception of the dolphin pool and the grand reef. Even those 2 areas are climate controlled so the water temperature is consistent regardless of the air temperature. Two of the water features, the Freshwater Oasis and the lazy river, are as warm as bathwater. If you are looking to warm up on a colder day, those areas are where to spend your time.
In colder weather, the park will have large heaters located in key areas throughout the park. They will be near the dining area, and other places where people can stand around them to help dry off and warm up. The wet suits that are provided to all guests will also help you stay warm on a day where the air temperature is on the coolside. That is what they are designed for.
We have been to discovery cove in every season. Our very 1st visit was during the month of January, and we had an amazing time. As of right now, discovery cove has a very flexible reschedule policy so if your vacation itinerary permits, you would be able to make a date switch at the last minute if there is availability. Just in case one day turns out to be forecast to be very cold while the rest of your vacation days are more moderate.
The blue Friday sales which are held on black Friday weekend each year have often held some very good offers for discovery cove. I personally would not want to wait that long to book a visit within 60 days or so of my vacation, but if you are willing to be patient it may pay off for you. You could always book your day now and cancel and rebook again if the blue Friday sales offer you is a better price than the current rate.
